The critical role of charged oxygen vacancies in Hf-based material systems toward advanced memory applications

Hf-based thin films hold promise for next-generation non-volatile and morphotropic beyond-Moore electronic devices. However, the fundamental mechanism of phase modulation remains unclear, hindering solutions to critical issues such as high coercive fields (Ec) and permittivity enhancement. Here, we report a physical framework linking phase modulation to charged oxygen vacancies ( V o 2 + ). The strong correlation between V o 2 + and phase modulation is demonstrated. Additionally, the current technological approaches, encompassing strain and doping engineering, can ultimately be attributed to the control of V o 2 + . This guides device experiments, achieving an ultra-low E c of 0.51 MV/cm in ferroelectrics and a record-high permittivity of ∼83 in morphotropic devices, alongside robust reliability. This work develops a unified theory in the phase modulation of Hf-based material systems, opening a reliable pathway for the advancement of next-generation beyond-Moore electronic devices.